54 lines
1.9 KiB
Diff
54 lines
1.9 KiB
Diff
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From 566844b93e6823a04ed65827ba3e03cb123b3a03 Mon Sep 17 00:00:00 2001
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From: Khem Raj <raj.khem@gmail.com>
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Date: Wed, 18 Jan 2023 00:32:36 -0800
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Subject: [PATCH] Define alignof using _Alignof when using C11 or newer
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WG14 N2350 made very clear that it is an UB having type definitions
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within "offsetof" [1]. This patch enhances the implementation of macro
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alignof_slot to use builtin "_Alignof" to avoid undefined behavior on
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when using std=c11 or newer
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clang 16+ has started to flag this [2]
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Fixes build when using -std >= gnu11 and using clang16+
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Older compilers gcc < 4.9 or clang < 8 has buggy _Alignof even though it
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may support C11, exclude those compilers too
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[1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm
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[2] https://reviews.llvm.org/D133574
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Upstream-Status: Pending
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Signed-off-by: Khem Raj <raj.khem@gmail.com>
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Signed-off-by: Jes Sorensen <jes@trained-monkey.org>
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---
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sha1.c | 12 +++++++++++-
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1 file changed, 11 insertions(+), 1 deletion(-)
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diff --git a/sha1.c b/sha1.c
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index 89b32f4..1e4ad5d 100644
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--- a/sha1.c
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+++ b/sha1.c
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@@ -229,7 +229,17 @@ sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx)
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if (len >= 64)
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{
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#if !_STRING_ARCH_unaligned
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-# define alignof(type) offsetof (struct { char c; type x; }, x)
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+/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023
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+ <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>.
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+ clang versions < 8.0.0 have the same bug. */
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+# if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \
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+ || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \
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+ && !defined __clang__) \
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+ || (defined __clang__ && __clang_major__ < 8))
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+# define alignof(type) offsetof (struct { char c; type x; }, x)
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+# else
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+# define alignof(type) _Alignof(type)
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+# endif
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# define UNALIGNED_P(p) (((size_t) p) % alignof (sha1_uint32) != 0)
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if (UNALIGNED_P (buffer))
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while (len > 64)
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--
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2.35.3
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